The present invention generally relates to a method and structure for adding an auxiliary lifting unit to a mobile crane. In particular, it deals with an assembly system for a mobile crane auxiliary lifting unit, and with a method for assembling a mobile crane auxiliary lifting unit; in addition, a footing support for a mobile crane auxiliary lifting unit is disclosed.
The use of auxiliary lifting units for augmenting the main lifting units is known in the mobile crane industry. Mostly, auxiliary lifting units are provided as separate units that can be added to a crane and employed as needed. To secure them to a crane, such auxiliary lifting units have assembly fastenings, which mostly are disposed on their frame parts and serve for fastening the auxiliary lifting unit to the crane.
Heretofore, the auxiliary lifting units, which have to be moved with power-assisted means due to their weight and their dimensions, are mostly moved and assembled, i.e. lifted and then fastened to a rotary table receptacle, with the aid of a traditional counterweight lifting system found on the crane.
Disadvantageously, this approach entails a high demand of work and attention by the operating personnel in order to accomplish the exact assembly of the auxiliary lifting unit by means of a lifting unit that is actually designed to move counterweights.
Against this background, it is the object of the present invention to provide an assembly system, as well as a method for assembling a mobile crane auxiliary lifting unit, which results in the connection of such an auxiliary lifting unit to a crane in an improved manner. In particular, the assembly can be performed with a reasonable amount of work, time, and attention.